Novel pharmaceutical compounds

ABSTRACT

Novel compounds and pharmaceutical compositions are provided. In one aspect of the invention the compounds may be utilized in medical practice, for example, in treatment of cancer and immune disorders.

FIELD OF THE INVENTION

The invention relates to the field of drug therapy for medicaldisorders. Specifically, the invention relates to novel compounds andpharmaceutical compositions that may be utilized in medical practice,for example, for treatment of cancer.

BACKGROUND OF THE INVENTION

Drug therapy for medical disorders often requires improvement in aspectssuch as pharmacokinetics, efficacy, or adverse effects. For example,many anti-cancer drugs have a very narrow therapeutic window, i.e., asmall difference between the drug levels required to exert a beneficialanti-tumor effect, and those causing adverse effects, some of which maybe dose-limiting or life-risking. As another example, it is oftendesirable for many drugs used in various fields, such as anti-cancerdrugs, anti-inflammatory drugs, or drugs used to treat neurological orpsychiatric disorders, to be administered as inactive pro-drugs, with asubsequent slow, sustained release of the active drug, thereby enablingprolonged drug circulation time and prolonged drug activity at itstarget sites. Furthermore, it is often desirable for a drug, to betargeted to a focus of disease, i.e., to have, following itsadministration to the patient, a concentration gradient between targetand non-target tissues, with relatively high levels of the pro-drugand/or the active drug at the foci of disease, compared to non-targettissues.

SUMMARY OF THE INVENTION

The invention concerns novel chemical compounds and novel pharmaceuticalcompositions, for the treatment of medical disorders.

According to one embodiment, the novel compounds and novelpharmaceutical compositions of the invention may be used for thetreatment of cancer.

In one embodiment there is provided a compound represented by thestructure of Formula I:

-   -   in which    -   R¹ and R² are the same or different, each being independently        selected from C₁, C₂, C₃, C₄, C₅, C₆, C₇ or C₈ linear, branched        or cyclic alkyl, aryl or heteroaryl;    -   R³ is selected from hydrogen, C₁, C₂, C₃, C₄, C₅, C₆, C₇ or C₈        linear or branched alkyl;    -   L is selected from C₁, C₂, C₃, C₄, C₅, C₆, C₇ or C₈ linear,        branched or cyclic alkyl, C₁, C₂, C₃, C₄, C₅, C₆, C₇ or C₈        linear, branched or cyclic alkyl-amine, aryl, heteroaryl or a        combination thereof;    -   U is selected from —O—; —(CO)O—; —O(CO)—NH—; or —(CO)—NH—;    -   n and m are integers, each being independently selected from 0,        1, 2, 3, 4; and    -   D is a drug.

According to one embodiment R¹ and R² are each a tert-butyl group, R³ isa methyl group, n=1 and m=1.

In another embodiment there is provided a compound, comprising thestructure as set forth in Formula IX:

in which R¹ and R² are the same or different, each being independentlyselected from C_(I), C₂, C₃, C₄, C₅, C₆, C₇ or C₈ linear, branched orcyclic alkyl, aryl or heteroaryl; R³ is selected from hydrogen, C₁, C₂,C₃, C₄, C₅, C₆, C₇ or C₈ linear or branched alkyl; n and m are integers,each being independently selected from 0, 1, 2, 3, 4; and * stands for alinkage point to a drug, either directly or through a linker L, asdefined above.

The term “drug” for the purpose of the present invention relates to amedicinally-useful chemical compound, which upon administration to asubject with a disease, exerts a pharmacological effect, such as helpingto cure the disease, reducing its extent, or alleviating its symptoms orsigns.

The term “conjugate” for the purpose of the present invention, relatesto a molecule that comprises two (or more) chemical moieties, linkedtogether by any means known in the art.

The term “therapeutically effective dose” relates, for example, to anamount of drug that elicits a therapeutically useful response, either intreatment of an existing medical disorder, and/or in preventing ordelaying the disease onset, in an animal or a human subject.

BRIEF DESCRIPTION OF THE FIGURES

The invention will now be described in relation to certain examples andpreferred embodiments, with reference to the following illustrativefigures. In the Figures:

FIG. 1 shows the efficacy of ATT-11T (a compound according to anembodiment of the invention) as a cytotoxic anti-cancer drug, asexemplified in cultured A375-melanoma cells in vitro, in comparison withthe anti-cancer drug CPT-11 (irinotecan), which is a pro-drug of SN-38,an anti-cancer agent, active as an inhibitor of the enzyme topoisomeraseI. A375 cells were incubated with increasing concentrations of ATT-11Tor CPT-11, and cell viability was assessed. The cytotoxic effect ofthese agents was expressed as the percentage of viable cells at 24 hoursof incubation. ATT-11T exhibited potent cytotoxic effect, with IC₅₀(inhibitory concentration of 50% of cells) of 3.3 μM, being more potentthan CPT-11. Therefore, as shown, ATT-11T is a potent anti-cancer agent.

FIG. 2 shows the performance of ATT-11T in inhibiting tumor growth intumor-bearing nude mice. A375 melanoma tumor-bearing mice were treatedwith ATT-11T (5 or 20 mg/kg×9), and tumor volumes (mm³) were measured,in comparison with the tumor volumes in control, untreated mice. ATT-11Texerted a dramatic effect on the tumors, with complete tumor regressionand growth inhibition, observed with both doses of the drug.

FIG. 3 demonstrates the anti-cancer effect of ATT-11T, causingregression and growth inhibition of melanoma A375 tumors in nude mice.Upper panels (A,B) shows representative tumors from untreated animals,while the lower panels (C,D) show the tumor inoculation sites (arrows)in animals treated with a relatively low dose (5 mg/kg×9) of ATT-11T. Asshown, ATT-11T exerted a potent anti-cancer effect, causing tumorregression and tumor growth inhibition.

FIGS. 4A and 4B show tumor growth delay, exerted by ATT-11T in melanomaA375 tumor-bearing mice. Tumor-bearing mice were treated with ATT-11T (5mg/kg or 20 mg/kg×9), or CPT-11 (75 mg/kg×3), and tumor growth wasfollowed for one month after the last dose. As shown, ATT-11T at bothdoses substantially inhibited tumor growth, even at one month after thelast dose, as compared to CPT-11.

FIG. 5 shows lack of adverse effect of ATT-11T on body weight in themelanoma A375 tumor-bearing mice. Tumor-bearing mice were treated withATT-11T and were weighed twice a week. As shown, concurrently with thesubstantial tumor inhibitory effect ATT-11T as described above, the drugwas well-tolerated, without causing loss of body weight.

FIGS. 6A and 6B show the pharmacokinetic profile of ATT-11T, as comparedto CPT-11 in beagle dogs. FIG. 6A shows plasma concentrations of theparent drugs ATT-11T or CPT-11 vs. time, while FIG. 6B shows the plasmaconcentrations of the common active cytotoxic metabolite SN-38 vs. time.As shown, ATT-11T was characterized by favorable profile, with sustainedplasma levels and slow clearance of both the parent drug and its activemetabolite SN-38, as compared to CPT-11.

FIGS. 7A and 7B show the plasma half-life (t_(1/2)) of the parent drugs(ATT-11T or CPT-11, FIG. 7A), or the active cytotoxic metabolite SN-38,respectively derived from ATT-11T or CPT-11 (FIG. 7B), followingintravenous drug administration to dogs, SN-38 derived from ATT-11Tmanifested a 5.2-fold longer plasma half-life, as compared to SN-38derived from CPT-11.

FIGS. 8A and 8B show the area under the plasma concentration/time curve(AUC) of the parent drug (ATT-11T or CPT-11, FIG. 8A), or the commonactive cytotoxic metabolite SN-38 derived respectively from ATT-11T orCPT-11 (FIG. 8B), following intravenous drug administration to beagledogs. AUC of ATT-11T was 4-fold larger than that of CPT-11, and the AUCof SN-38 derived from ATT-11T was 2.9-fold larger than the AUC of SN-38derived from CPT-11. Therefore, administration of ATT-11T resulted in asubstantially longer exposure to both the parent drug and to its activemetabolite SN-38, as compared to CPT-11.

DETAILED DESCRIPTION OF THE INVENTION

In one embodiment there is provided a compound represented by thestructure of Formula (I):

-   -   in which    -   R¹ and R² are the same or different, each being independently        selected from C₁, C₂, C₃, C₄, C₅, C₆, C₇ or C₈ linear, branched        or cyclic alkyl, aryl or heteroaryl;    -   R³ is selected from hydrogen, C₁, C₂, C₃, C₄, C₅, C₆, C₇ or C₈        linear or branched alkyl;    -   L is selected from C₁, C₂, C₃, C₄, C_(s), C₆, C₇ or C₈ linear,        branched or cyclic alkyl, C₁, C₂, C₃, C₄, C₅, C₆, C₇ or C₈        linear, branched or cyclic alkyl-amine, aryl, heteroaryl or a        combination thereof;    -   U is selected from —O—; —(CO)O—; —O(CO)—NH—; or —(CO)—NH—;    -   n and m are integers, each being independently selected from 0,        1, 2, 3, 4; and    -   D is a drug.

According to one embodiment, n=1 and m=1.

According to one embodiment R¹ and R² are each a tert-butyl group, [i.e.—C(CH₃)₃], and the compound is represented by the structure of Formula(II):

According to one embodiment R³ is a methyl.

According to another embodiment, there is provided a compoundrepresented by the structure of Formula (III):

in which k is an integer of 1, 2, 3, 4, or 5.

According to another embodiment there is provided a compound representedby the structure of Formula (IV):

in which k is an integer of 1, 2, 3, 4, or 5.

According to another embodiment there is provided a compound representedby the structure of Formula (V):

in which k is an integer of 1, 2, 3, 4, or 5.

According to one embodiment k is 5 and D is either ibuprofen orlevodopa.

According to one embodiment there is provided a compound represented bythe structure of Formula (VI):

in which L is as defined above.

According to one embodiment there is provided a compound represented bythe structure of Formula (VII):

The compound of Formula VII is designated ATT-11T.

According to another embodiment there is provided a compound representedby the structure of Formula (VIII):

The compound of Formula (VIII) is designated ATT-20.

Embodiments of the invention also provide pharmaceutically acceptablesalts, hydrates, solvates and metal chelates of any of the compounds ofFormulae I, II, III, IV, V, VI, VII, or VIII, and pharmaceuticalcompositions containing the compound.

According to some embodiments D is an anti-cancer drug. For example, Dcan be an inhibitor of topoisomerase, such as camptothecin orderivatives or analogues thereof (for example in Formulae VI and VII);or 5-fluorouracil or analogues thereof, such as capecitabine (forexample, in Formula VIII).

According to some embodiments of the invention, D may be ananti-inflammatory drug, a drug for the treatment of immune-mediateddisorders, a drug for the treatment of infectious disorders, a drug forthe treatment of vascular disorders, a drug for the treatment of toxicdisorders, a drug for the treatment of neurological disorders, or a drugfor the treatment of psychiatric disorders.

According to some embodiments there is provided a compound, comprisingthe structure as set forth in Formula IX:

in which R¹ and R² are the same or different, each being independentlyselected from C₁, C₂, C₃, C₄, C₅, C₆, C₇ or C₈ linear, branched orcyclic alkyl, aryl or heteroaryl; R³ is selected from hydrogen, C₁, C₂,C₃, C₄, C₅, C₆, C₇ or C₈ linear or branched alkyl; n and m are integers,each being independently selected from 0, 1, 2, 3, 4; and * stands for alinkage point to a drug, either directly or through a linker L, asdefined above.

According to one embodiment, R¹ and R² are each a tert-butyl group.

According to one embodiment, n=1 and m=1.

According to one embodiment R³ is CH₃

According to one embodiment, there is provided a compound, comprisingthe structure as set forth in Formula X:

wherein * stands for a linkage point to a drug, either directly orthrough a linker L, as defined above.

According to some embodiments, the compounds comprising the structuresof Formulae (IX) or (X) may be used in the preparation of a medicament,for example, in the preparation of an anti-cancer drug.

According to some embodiments, the compounds of Formulae (IX) or (X) maybe used in the preparation of a conjugate, which optionally includes alinker connecting the compound of Formulae IX or X to a drug.

According to some embodiments of the invention, there is provided amethod for the treatment of medical disorders, the method comprisingadministering to a subject having a medical disorder a therapeuticallyeffective dose of any of the compounds represented by Formulae I, II,III, IV, V, VI, VII or VIII, wherein D is a drug, useful for thetreatment of said medical disorder.

According to an embodiment of the invention, said medical disorder iscancer.

Compounds according to embodiments of the invention all have the commonfeature represented by Formula IX and more specifically, according tosome embodiments, the compounds have the common feature represented byFormula X, which provides improved efficacy and drug performance inparameters such as oral bioavailability, selectivity and an improvedpharmacokinetic profile.

In one embodiment of the invention, the conjugate having the structureset forth in Formula (VII) and designated ATT-11T comprises theanti-cancer drug SN-38.

ATT-11T is a carbamate pro-drug of the anti-cancer agent SN-38. Uponcleavage of the carbamate bond by esterases in the body, SN-38 isreleased to exert its cytotoxic effect through inhibition of the enzymetopoisomerase I.

In another embodiment of the invention, the conjugate having thestructure set forth in Formula (VIII) and designated ATT-20T, comprisesthe anti-cancer drug capecitabin.

Embodiments of the invention provide a method for treatment of disease,by administering to the subject having the disease a compound, atherapeutically effective amount of conjugate or a pharmaceuticalcomposition comprising any one of the compounds set forth in Formulae I,II, III, IV, V, VI, VII or VIII.

The compounds of the invention can be active as therapeutic agents bythemselves, i.e., without any further structural modifications, or mayact as pro-drugs, i.e., capable of exerting a pharmacological actiononly after metabolic conversion in the body. Among others, saidconversion can be enzymatic cleavage of the molecule of the invention atthe respective ester, amide or carbamate moieties, as applicable for thespecific compound.

In an embodiment of the invention there is provided a method fortreatment of medical disorders, wherein said medical disorder areselected from cancer, inflammatory disorders, immune-mediated disorders,infectious disorders, vascular disorders, toxic disorders, neurologicaldisorders, or psychiatric disorders.

Embodiments of the invention provide a pharmaceutical compositioncomprising a compound or conjugate according to any of Formulae I, II,III, IV, V, VI, VII or VIII, as described above and/or as described inthe Examples below, and pharmaceutically acceptable salts, hydrates andsolvates thereof and solvates and hydrates of the salts.

Some examples of salts include nontoxic alkaline metal salts, alkalineearth metal salts and ammonium salts such as sodium, potassium, lithium,calcium, magnesium, barium and ammonium salts. In addition, nontoxicacid addition salts are also included in the above-mentioned salts, forexample, hydrochlorides, hydrogen chlorides, hydrogen bromides,sulfates, bisulfates, acetates, oxalates, valerates, oleates, laurates,borates, benzoates, lactates, malates, p-toluene sulfonates (tosylates),citrates, maleates, fumarates, succinates, tartrates, sulfonates,glycolates, maleates, ascorbates and benzene sulfonates.

Pharmaceutical compositions according to embodiments of the inventionmay include a pharmaceutically accepted carrier such as a diluent,adjuvant, excipient, or vehicle with which the therapeutic agent isadministered. Some examples of pharmaceutically acceptable carriersinclude water, salt solutions, alcohol, silicone, waxes, petroleumjelly, vegetable oil, peanut oil, soybean oil, mineral oil, sesame oil,polyethylene glycols, propylene glycol, liposomes, sugars, gelatin;lactose, amylose, magnesium stearate, talc, surfactants, silicic acid,viscous paraffin, perfume oil, fatty acid monoglycerides anddiglycerides, petroethral fatty acid esters, hydroxymethyl-cellulose,polyvinylpyrrolidone, and the like.

The pharmaceutical compositions may be manufactured, for example, bymeans of conventional mixing, dissolving, granulating, levitating,emulsifying, encapsulating, entrapping, lyophilizing processes or othersuitable processes.

The pharmaceutical compositions can take the form of solutions,suspensions, emulsions, tablets, pills, capsules, powders,sustained-release Formulations and the like, depending on the intendedroute of administration. Examples of routes of administration includeparenteral, e.g., intravenous, intramuscular, subcutaneous,intra-arterial, intraportal, intrathecal, intradermal, transdermal(topical), transmucosal, intra-articular, intraperitoneal, andintrapleural, as well as intrathecal, intracerebral, inhalation andpulmonary administration. In another aspect, the delivery system andpharmaceutical composition are administered to the subject locally, forexample, by injection to a local blood vessel which supplies blood to aparticular tumor, organ, tissue, or cell afflicted by disorders ordiseases.

For example, for parenteral administrations, the composition maycomprise one or more of the following components: a sterile diluent suchas water for injection, saline solution; antibacterial agents such asbenzyl alcohol or methyl parabens; antioxidants such as ascorbic acid orsodium bisulfite; chelating agents such as ethylenediaminetetraaceticacid; buffers such as acetates, citrates or phosphates and agents forthe adjustment of tonicity such as sodium chloride or dextrose. Theparenteral preparation can be enclosed in ampules, disposable syringesor multiple dose vials made of glass or plastic.

For example, for injection, the conjugates of the invention may beFormulated in aqueous solutions, preferably in physiologicallycompatible buffers such as physiological saline buffer. The solution maycontain Formulatory agents such as suspending, stabilizing and/ordispersing agents. In a preferred embodiment, the delivery systems areformulated in sterile aqueous solutions.

For example, for intravenous administration, suitable carriers includephysiological saline, bacteriostatic water, or phosphate buffered saline(PBS). In all cases, the composition must be sterile and, when injected,should be fluid to the extent that easy injectability with a syringe.Compositions may include preservatives such as, parabens, chlorobutanol,phenol, ascorbic acid, thimerosal, and the like.

The pharmaceuticals according to embodiments of the invention can beadministered orally, for example in the form of pills, tablets,lacquered tablets, sugar-coated tablets, granules, hard and soft gelatincapsules, aqueous, alcoholic or oily solutions, syrups, emulsions orsuspensions. For the production of pills, tablets, sugar-coated tabletsand hard gelatin capsules it is possible to use, for example, lactose,starch, for example maize starch, or starch derivatives, talc, stearicacid or its salts, etc. Carriers for soft gelatin capsules andsuppositories are, for example, fats, waxes, semisolid and liquidpolyols, natural or hardened oils, etc. Suitable carriers for thepreparation of solutions, for example of solutions for injection, or ofemulsions or syrups are, for example, water, physiological sodiumchloride solution, alcohols such as ethanol, glycerol, polyols, sucrose,invert sugar, glucose, mannitol, vegetable oils, etc. In one embodiment,the medicament, together with one or more auxiliary excipient materialsmay be compressed into a tablet form such as a single layer ormultilayer tablet. Tablets according to embodiments of the invention canoptionally be coated with a controlled release polymer so as to provideadditional controlled release properties.

For example, for administration by inhalation, the delivery systems maybe formulated as an aerosol spray from pressurized packs or a nebulizer,with the use of a suitable propellant, e.g., dichlorodifluoromethane,trichlorofluoromethane, dichlorotetrafluoroethane, carbon dioxide orother suitable gas.

Various doses can be used, and doses may be administered in variousintervals, according to the disease, the clinical status of the patientor concomitant medications. Dosage can vary, according to the clinicaljudgment of the physician.

Embodiments of the invention provide methods for treatment of medicaldisorders. According to an embodiment of the invention, one methodcomprises administering to a subject (human or animal) a therapeuticallyeffective dose of a compound or a pharmaceutical composition accordingto any of the Formulae I, II, III, IV, V, VI, VII or VIII. Said compoundor pharmaceutical composition may be administered with additives, suchas those described above, and administration may take any suitableroute, such as those described above.

In one aspect of the invention, the compound according to any ofFormulae I, II, III, IV, V, VI, VII or VIII has anti-cancer activity,i.e. is capable of causing damage to and/or killing tumor cells, eitherby itself, or upon its cleavage to an active metabolite. According tothis aspect of the invention, said compound or related pharmaceuticalcomposition may be used for the treatment of cancer, wherein thetumor(s) may involve or originate from any organ in the body.

In one embodiment, the types of cancer to be treated by the compounds ofthe invention and/or their related pharmaceutical compositions includeprimary or secondary tumors of the lung, colon, breast, melanoma,lymphoma, prostate, thyroid, testes, ovary, skin, brain or bone.

In another aspect of the invention, the compound according to any ofFormulae I, II, III, IV, V, VI, VII or VIII comprises a drug that isuseful for the treatment of a medical disorder, selected frominflammatory disorders, immune-mediated disorders, infectious disorders,vascular disorders, toxic disorders, psychiatric disorders orneurological disorders. According to this aspect of the invention, acompound or related pharmaceutical composition of the invention may beused for the treatment of the respective medical disorder.

According to some embodiments of the invention, the compounds or theirrelated pharmaceutical compositions may be used as monotherapy, i.e., asa single chemotherapeutic agent, or in combination with othertherapeutic agents, i.e., as part of a combination therapy. Treatmentcan be acute or chronic.

Some examples will now be described, in order to further demonstrate theinvention, and to exemplify how embodiments of the invention may becarried-out in practice. The examples illustrate, in a non-limitingmanner, an exemplary method for the preparation of a compound accordingto one embodiment of the invention, and biological performance in tumorinhibition, both in vitro and in vivo, in xenograft animal models ofcancer. In addition, a favorable pharmacokinetic profile of a compoundof the invention is demonstrated, as examined in beagle dogs.

EXAMPLES Example 1

An exemplary method for preparation of the compound designated ATT-11Tis demonstrated. However, modifications of this method (e.g., similarprocesses including additional or other steps known in the art such asalkylation, hydration, condensation, as well as other steps), which mayresult in similar compounds, are also included in embodiments of theinvention.

The synthetic scheme for ATT-11T according to one embodiment of theinvention is illustrated below. As a first step, Boc protection ispreformed on a piperidine derivative 1, followed by bromination toobtain compound 3, and condensation with diethyl-methyl malonate, whichis produced by methylation of di-ethyl malonate 4. Said condensationresults in compound 6A, which is then reduced, to obtain compound 6B.Subsequently, etherification is performed, in order to obtain compound7. Compound 7 is then Boc-de-protected and condensed with SN-38(compound 10), to result in compound 11, i.e., the desired productATT-11T. This synthetic route is further illustrated in the followingsynthetic scheme:

Example 2

This example demonstrates the efficacy of ATT-11T as an anti-cancer drugin vitro.

The efficacy of ATT-11T as an anti-cancer drug is exemplified incultured A375-melanoma cells in vitro, in comparison with thecommercially available anti-cancer drug CPT-11 (irinotecan), which is apro-drug of the topoisomerase inhibitor SN-38. A375 cells were incubatedwith increasing concentrations of either ATT-11T or CPT-11, cellviability was evaluated, and IC₅₀ (inhibitory effect of 50% cells) wascalculated.

Cells were grown in RPMI 1640 (Gibco, UK) supplemented with 10% FBS(Gibco, UK) 2 mM of L-glutamin (Gibco, UK), 20 mM HEPES buffer(Beit-Haemek, Israel), 100 units/ml of penicillin, and 100 μg/ml ofstreptomycin (Gibco, UK). Cells were cultured in humidified atmospherecontaining 5% CO₂ at 37° C. Medium was routinely changed twice a week,and cells were sub-cultured with 0.25% trypsin/EDTA (Beit-Haemek,Israel) when reaching 85% confluence.

ATT-11T was produced by Aptuit-Laurus (India). The compound wasdissolved in DMSO. Irinotecan (CPT-11) was supplied as irinotecanhydrochloride trihydrate (Pfizer), and was diluted from a concentratestock solution of 100 mg/5 ml. The cells were incubated for 24 hours at37° C. with serial dilutions of ATT-11T (or CPT 11), dissolved ingrowing medium. Cell viability was then determined, using the XTTreagent (Beit-Haemek, Israel). At the end of the incubation period,tetrazolium dye was added, and formation of a colored product formazanwas measured at 450 nm using a microplate reader (ELx800, Bio-Tekinstruments Inc.). Cell viability vs. drug concentration was plotted,and data were fitted with a non-linear regression analysis usingGraphPad prisma ver. 5.0 software. IC₅₀ values of ATT-11T and CPT-11were then calculated as the drug concentration that inhibited 50% of thecell growth, as compared to untreated cells, which served as controls.

The results of a representative study are displayed in FIG. 1, showingthe percentage of viable cells over time, as compared to untreatedcontrols. As shown, ATT-11T manifested a marked cytotoxic effect; withan IC₅₀ of 3.4 μM. Potency of ATT-11T was substantially larger than thatof CPT-11, which exhibited an IC₅₀ of 10.1 μM. These results thereforeindicate that ATT-11T is a potent cytotoxic anti-cancer agent.

Example 3

This example demonstrates the efficacy of ATT-11T in inducing tumorregression and in inhibiting tumor growth in a xenograft model ofmelanoma in nude mice in vivo.

Subcutaneous A375 melanoma tumors were established in mice by injectionof A375 melanoma cells (0.75×10⁶ per animal per site) into the rightflank region of athymic nude mice (female, 8-9 weeks, 10 animals pergroup). Tumor dimensions were measured with a caliper twice each weekand tumor volume (mm³) was calculated using the Formula: TV=0.52L×W²,where L and W are the major and minor dimensions, respectively. Drugtreatment was initiated on day 10, when tumors reached an average volumeof 75-100 mm³. ATT-11T was administered intravenously into the tail veinof the mice, in a vehicle comprising 10% DMSO and 10% bovine serumalbumin (BSA) in 0.1M sodium phosphate buffer (pH 5.8). The drug wasadministered at a dose of either 5 or 20 mg/kg, given three times a weekfor three weeks. Tumor-bearing mice, injected only with the vehiclesolution served as controls.

FIG. 2 shows the tumor volume (mm³) vs. days after tumor inoculation. Asshown, ATT-11T manifested a dramatic inhibitory effect on tumor growth.While tumors of the control untreated animals manifested rapid growth,ATT-11T caused complete tumor regression and 100% growth inhibition,lasting at one week after the last administration of the drug. Thissubstantial effect of the drug was observed in both dose groups, i.e., 5mg/kg, and 20 mg/kg.

FIG. 3 (upper panel) demonstrates two representative tumors (A and B)from control untreated mice on day 29 after inoculation (one day afterthe last administration of the vehicle). Lower panel (C and D)demonstrates the tumor inoculation site (arrows) in two representativemice treated with 5 mg/kg of ATT-11T, on day 29, i.e., one day after thelast administration of the drug.

As shown, ATT-11T caused complete tumor regression and tumor growthinhibition, thus demonstrating its potent anti-cancer activity in vivo.

Example 4

This example demonstrates the efficacy of ATT-11T in inducing delay intumor growth in a xenograft model of melanoma in nude mice in vivo.

The rate of tumor growth following the last dose of chemotherapy wasassessed for ATT-11T, in comparison with that of CPT-11 (irinotecan).Drugs, i.e., ATT-11T or CPT-11 were administered intravenously into thetail vein of A375 melanoma-bearing mice, as described above (10 animalsper group). CPT-11 was administered as hydrochloride trihydrate (Pfizer,USA), diluted from a concentrate stock solution of 100 mg/5 ml. ATT11-T(Aptuit-Luarus, India) was administered in a vehicle as described above.Tumor-bearing mice injected only with the vehicle solution served ascontrols. ATT-11T was administered at a dose of either 5 or 20 mg/kg,given twice a week for three weeks. CPT-11 was administered at a dose of75 mg/kg, given once a week for three weeks. Tumor volume was evaluatedas described above.

Drug-induced delay in tumor growth was assessed by two measures: (i).Tumor volume inhibition (TVI %) at one week after the last treatment intreated versus control tumors, which was calculated according to theFormula TVI(%)=(1−TIC)×100, where T and C are the tumor volume of thetreated and control groups, respectively; and (ii). Tumor growth delay(TGD), assessed as the time period (days) of treatment-induced delay intumor reaching a pre-determined volume of 3,500 mm³, as compared to thevehicle-treated controls.

As shown in FIG. 4A and FIG. 4B, both doses of ATT-11T (5 mg/kg or 20mg/kg, respectively) caused a substantial inhibition of tumor growth,with complete tumor regression, (TVI of 100%) at one week after the lastdose of either dose of the drug. While CPT-11 manifested marked tumorinhibition, it never reached the complete tumor regression observed withATT-11T, and culminated in TVI of 95% at one week after the last dose ofthe drug.

Assessment of the tumor growth rate 30 days following the last dose oftreatment (58 days after tumor cell inoculation) revealed rapid tumorgrowth in the CPT-11-treated group, starting soon after theadministration of the last dose of the drug. Accordingly, the controlgroup and the CPT-11 group reached the endpoint tumor volume of 3,500mm³ on days 35 and 53 post tumor inoculation, respectively. By contrast,the animals treated with ATT-11T showed little (at the dose of 5 mg/kg,FIG. 4A) or no growth (at the dose of 20 mg/kg, FIG. 4B) even at day 30after the last dose of the drug.

Taken together, these results indicate that ATT-11T has potentanti-tumor properties, being able to induce both tumor regression andprolonged inhibition of tumor growth.

Example 5

This example evaluates potential adverse effects of ATT-11T intumor-bearing nude mice

For the evaluation of potential adverse effects of ATT-11T, nude mice,bearing the A375 melanoma tumors and treated with ATT-11T as describedabove, were monitored for adverse effects immediacy after drugadministration, and also twice a week, through one day after last dose.The evaluation protocol consisted of gross observation, registration ofabnormal signs, and determination of body weight. Potential body weightloss (BWL) was calculated as % BWL=100−(BW_(dayx)/BW_(day1)×100), whereday 1 is the first day of treatment and day x is the day of assessmentthereafter.

As shown in FIG. 5 in terms of % of initial weight per day starting atday 1 of treatment (day 10 after inoculation) up to day 29 ofinoculation, neither loss of body weight nor other adverse effects wereobserved. The ATT-11T-treated animals gained weight, with the animalstreated with 5 mg/kg gaining 7% of initial body weight, and the animalstreated with 20 mg/kg gaining 5%.

Therefore, as assessed in these experimental systems, concurrently withits marked effect in induction of tumor regression and in inhibitingtumor growth as described above, ATT-11T was well-tolerated at bothdoses, without observable adverse effects or weight loss.

Example 6

This example demonstrates pharmacokinetic properties of ATT-11T in dogs

A pharmacokinetics study was performed in beagle dogs, following asingle intravenous administration of ATT-11T, while CPT-11 served ascomparator. Both drugs were administered to female beagle dogs (AuricoopLtd, Hungary) at a dose of 6 mg/kg, with subsequent measurement ofplasma concentrations over time of both the parent drugs (ATT-11T orCPT-11) and the common active cytotoxic metabolite SN-38.

For this experiment, ATT-11T (Aptuit-Laurus, India), was dissolved inDMSO to prepare a clear stock solution of 50 mg/ml. The stock solutionwas diluted 10-fold in 10% bovine serum albumin solution in 0.1M sodiumphosphate buffer (pH 5.8) and mixed by vortex until a homogeneousemulsion was obtained. CPT-11 (irinotecan hydrochloride trihydrate,Pfizer, USA) was diluted from a concentrate stock solution of 100 mg/5ml. Fresh formulations of both drugs were prepared prior to eachadministration, and the drugs were administrated by a slow bolusinjection within approximately 3 minutes, at a dose of 6 mg/kg (1.2ml/kg), adjusted to the individual animal body weight.

For determination of plasma levels of ATT-11T, CPT-11 and SN-38, samplesof approximately 3 ml of blood each were collected into EDTA coatedvials, containing 75 μl dichlorvos (esterase inhibitor) solution (1.2%(V/V) dichlorvos in saline). Samples were collected once before dosing(0 min) and then at 5 min, 15 min, 30 min, 1 h, 2 h, 4 h, 8 h, 24 h, 48h, 72 h and 96 h after dosing. Plasma was separated by centrifugation,and stored at −70° C. until HPLC analysis. WinNonlin™ software was usedfor the analysis of the pharmacokinetic data.

FIG. 6A shows plasma concentrations of the parent drugs ATT-11T orCPT-11 vs. time, while FIG. 6B shows the plasma concentrations of thecommon active cytotoxic metabolite SN-38 vs. time. As shown, ATT-11T wascharacterized by sustained plasma levels and slow clearance of both theparent drug and its active metabolite SN-38, as compared to CPT-11.While SN-38 derived from CPT-11 was below detection level already at 24hours after administration, significant levels of SN-38 derived fromATT-11T were still detectable in the plasma at 48 hours afteradministration.

FIGS. 7A and 7B show the plasma half-life (t_(1/2); the time taken toreach a 50% reduction in plasma drug levels) of the parent drug (ATT-11Tor CPT-11, FIG. 7A), or the active cytotoxic metabolite SN-38, derivedrespectively from ATT-11T or CPT-11 (FIG. 7B), following intravenousadministration to dogs. ATT-11T showed a t_(1/2) of 25.6 hours comparedwith 6.8 hours for CPT-11, thus reflecting a 3.8-fold increase int_(1/2) of ATT11-T over CPT-11 in dogs. Moreover, SN-38 derived fromATT-11T manifested a 5.2-fold longer plasma half-life, as compared toSN-38 derived from CPT-11.

FIGS. 8A and 8B show the area under the plasma concentration/time curve(AUC) of the parents drug (ATT-11T or CPT-11, FIG. 8A), or the activecytotoxic metabolite SN-38 derived respectively from ATT-11T or CPT-11(FIG. 8B), following intravenous administration to beagle dogs. AUC ofATT-11T was 4-fold larger than that of CPT-11, and the AUC of SN-38derived from ATT-11T was 2.9-fold larger than the AUC of SN-38 derivedfrom CPT-11.

Taken together, the results of the pharmacokinetic study in the dogdemonstrate a favorable profile, with prolonged exposure to both ATT-11Tand its active metabolite SN-38, as compared to CPT-11.

Example 7

This example describes several conjugates within the scope of theinvention.

Each conjugate comprises the structure as set forth in Formula X,linked, either directly or through a linker (L) according to Formula(I), to a drug (D), used for the treatment of a medical disorder. Saidmedical disorder may be selected from cancer, inflammatory disorders,immune-mediated disorders, infectious disorders, vascular disorders,toxic disorders, psychiatric disorders or neurological disorders.

According to this aspect of the invention, the conjugate or relatedpharmaceutical composition of the invention may be used for thetreatment of the respective medical disorder.

One exemplary conjugate may be used for the treatment of inflammatorydisorders. This exemplary conjugate is represented by the structure ofFormula V′, which includes the structure of Formula X and theanti-inflammatory drug ibuprofen:

Another exemplary conjugate may be used for the treatment of Parkinson'sdisease. This exemplary conjugate is represented by the structure ofFormula V″ which includes the structure of Formula (X) and the druglevodopa:

These compounds can be evaluated in various pre-clinical models of therespective medical disorders, or in patients having the respectivediseases.

Efficacy of the compound according to Formula V′ can be evaluated inanimal models of inflammation, or in patients having inflammatorydiseases such as rheumatoid arthritis, or inflammatory bowel disease.

Efficacy of the compound according to Formula V″ can be evaluated inanimal models of Parkinson's disease, such as animals treated with theneurotoxin MPTP or 6-hydroxydopamine. Efficacy of this compound can alsobe evaluated in patients with Parkinson's′ disease, in alleviating theparkinsonian symptoms and signs, such as bradykinesia, rigidity, tremoror postural instability.

1. A compound represented by the structure set forth in Formula (I)

in which R¹ and R² are the same or different, each being independentlyselected from C₁, C₂, C₃, C₄, C₅, C₆, C₇ or C₈ linear, branched orcyclic alkyl, aryl or heteroaryl; R³ is selected from hydrogen, C₁, C₂,C₃, C₄, C₅, C₆, C₇ or C₈ linear or branched alkyl; L is selected fromC₁, C₂, C₃, C₄, C₅, C₆, C₇ or C₈ linear, branched or cyclic alkyl, C₁,C₂, C₃, C₄, C₅, C₆, C₇ or C₈ linear, branched or cyclic alkyl-amine,aryl, heteroaryl or a combination thereof; U is selected from —O—;—(CO)O—; —O(CO)—NH—; or —(CO)—NH—; n and m are integers, each beingindependently selected from 0, 1, 2, 3, 4; D is a drug; andpharmaceutically acceptable salts, hydrates, solvates and metal chelatesof the compound.
 2. The compound according to claim 1 comprising thestructure set forth in Formula (II)

and pharmaceutically acceptable salts, hydrates, solvates and metalchelates of the compound.
 3. The compound according to claim 2 whereinR³ is a methyl.
 4. The compound according to claim 3 comprising thestructure set forth in Formula (III)

wherein k is an integer of 1, 2, 3, 4 or 5; and pharmaceuticallyacceptable salts, hydrates, solvates and metal chelates of the compound.5. The compound according to claim 3 comprising the structure set forthin Formula (IV)

wherein k is an integer of 1, 2, 3, 4 or 5; and pharmaceuticallyacceptable salts, hydrates, solvates and metal chelates of the compound.6. The compound according to claim 3 comprising the structure set forthin Formula (VI)

and pharmaceutically acceptable salts, hydrates, solvates and metalchelates of the compound.
 7. The compound according to claim 6comprising the structure set forth in Formula (VII)


8. The compound according to claim 5 comprising the structure set forthin Formula (VIII)


9. The compound according to claim 1 wherein D is selected from thegroup consisting of: anti cancer drug, anti inflammatory drug, drug forthe treatment of immune-mediated disorders, drug for the treatment ofinfectious disorders, drug for the treatment of vascular disorders, drugfor the treatment of toxic disorders, drug for the treatment ofneurological disorders or drug for the treatment of psychiatricdisorders.
 10. The compound according to claim 9 wherein D is an anticancer drug.
 11. The compound according to claim 10 wherein D is atopoisomerase inhibitor.
 12. The compound according to claim 11 whereinD is a camptothecin or an analogue thereof.
 13. The compound accordingto claim 10 wherein D is 5-fluorouracil or an analogue thereof.
 14. Thecompound according to claim 13 wherein D is capecitabine.
 15. A compoundcomprising the structure set forth in Formula (IX)

wherein R¹ and R² are the same or different, each being independentlyselected from C₁, C₂, C₃, C₄, C₅, C₆, C₇ or C₈ linear, branched orcyclic alkyl, aryl or heteroaryl; R³ is selected from hydrogen, C₁, C₂,C₃, C₄, C₅, C₆, C₇ or C₈ linear or branched alkyl; and stands for alinkage point to a drug.
 16. The compound according to claim 15 whereinR¹ and R² are each —(CH₃)₃.
 17. The compound according to claim 15wherein R³ is —CH₃.
 18. A method for treatment of a medical disorder,the method comprising administering to a subject having a medicaldisorder a therapeutically effective dose of any of the compoundsrepresented by Formulae I, II, III, IV, V, VI, VII or VIII, wherein D isa drug useful for the treatment of said medical disorder.
 19. The methodaccording to claim 18 wherein the medical disorder is cancer, andwherein D is an anti-cancer drug.
 20. The method according to claim 19comprising administering to the subject a therapeutically effective doseof the compound represented by Formula (VII).
 21. The method accordingto claim 19 comprising administering to the subject a therapeuticallyeffective dose of the compound represented by Formula (VIII).